I have 21K hands 20NL @7.5PTBB/100 with a W$SD% of 50. W$SD% is constant between 55 and 56 over all BB ranges.

15K hands 50NL @-0.2PTBB/100, W$SD% 50. Here it's pretty constant too, about 53% at the smaller pots, 48-49 medium, 50-52 large pots.

Don't know what to think about these stats..